It's a legal requirement that an Air Traffic Controller must get a minimum 30 minute break every 2 hours. What you often see in staff shortages therefore is closures every 2 hours for 30 mins at a time, as there's nobody available to cover said breaks, which sounds like it may have happened here. The same thing has happened at least twice in DUB in recent weeks in the small hours of the morning. Pre COVID there was already a major shortage of Controllers globally. Then during the pandemic there were lots of redundancies, and anyone who retired wasn't replaced, so things are even worse now. It's by no means unique to MAN or NATS. Karlsruhe, Marseille, Barcelona and other en route centers are all very badly affected virtually every day.
Regarding Egyptair, they've been hoovering up passengers to South Africa in DUB, apparently they're a very good connecting option, so I should imagine they'll try for similar at MAN.